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7. Acids, bases and salts

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  1. 7.1 The characteristic properties of acids and bases

    1. • Describe characteristic properties of acids in terms of their reactions with: (a) metals (b) bases (c) carbonates

    2. • Describe acids in terms of their effect on: (a) litmus (b) thymolphthalein (c) methyl orange

    3. • State: bases are oxides or hydroxides of metals and that alkalis are soluble bases

    4. • Describe characteristic properties of bases in terms of their reactions with: (a) acids (b) ammonium salts

    5. • Describe alkalis in terms of their effect on: (a) litmus (b) thymolphthalein (c) methyl orange

    6. • State: aqueous solutions of acids contain H+ ions and aqueous solutions of alkalis contain OH– ions

    7. • Describe how to compare hydrogen ion concentration, neutrality, relative acidity and relative alkalinity in terms of colour and pH using universal indicator paper

    8. • Describe neutralisation reaction between an acid and an alkali to produce water, H+ (aq) + OH– (aq) → H2O (l)

    9. • Define acids as proton donors and bases as proton acceptors

    10. • Define a strong acid as an acid that is completely dissociated in aqueous solution and a weak acid as an acid that is partially dissociated in aqueous solution

    11. • State: hydrochloric acid is a strong acid, as shown by the symbol equation, HCl (aq) → H+(aq) + Cl –(aq)

    12. • State: ethanoic acid is a weak acid, as shown by the symbol equation, CH3COOH(aq) ⇌ H+(aq) + CH3COO–(aq)

  2. 7.2 Oxides

    1. 7.2.1Classify oxides as acidic

      • Classify oxides as acidic, including SO 2 and CO2, or basic, including CuO and CaO, related to metallic and non-metallic character

    2. 7.2.2Amphoteric oxides as oxides that react

      • Describe amphoteric oxides as oxides that react with acids and with bases to produce a salt and water

    3. 7.2.3Classify Al 2O3 and ZnO as amphoteric

      • Classify Al 2O3 and ZnO as amphoteric oxides

  3. 7.3 Preparation of salts

    1. • Describe preparation, separation and purification of soluble salts by reaction of an acid with: (a) an alkali by titration (b) excess metal (c) excess insoluble base (d) excess insoluble carbonate

    2. • Describe salt solubility rules: soluble sodium/potassium/ammonium salts and nitrates; chlorides except lead/silver; sulfates except barium/calcium/lead; insoluble carbonates except sodium/potassium/ammonium; insoluble hydroxides except sodium/potassium/ammonium/calcium (partial)

    3. • Define a hydrated substance as a substance that is chemically combined with water and an anhydrous substance as a substance containing no water

    4. • Describe preparation of insoluble salts by precipitation

    5. • Define the term water of crystallisation as the water molecules present in hydrated crystals, including CuSO4•5H2O and CoCl2•6H2O